RB1 and acute lymphoblastic leukemia: The genomic profile of chr+ cases was largely overlapping with that of chr- ETP/near ETP ALL, as both subgroups showed a high rate of abnormalities associated with HOXA over-expression and recurrent deletions of TCF7, CDKN1B, RB1, and/or NF1. In addition, abnormalities of epigenetic modulators, typical for immature T-ALL, were detected in 66% of cth+ cases [1, 18].